1. Field of the Invention
The present invention relates to a device for forming precise circular and arcuate cuts in a workpiece with a router.
2. Description of the Prior Art
Carpenters, furniture manufacturers, and hobbyists alike commonly cut out large circular pieces of wood to make a multitude of products ranging from tabletops to barrel covers. By attaching a common router to a swing arm of known length which is then anchored to a pivot point on a workpiece, the router can be moved along a circular path shaping the workpiece to the desired radius.
The following patents illustrate router guides for forming arcuate cuts in a workpiece.
U.S. Pat. No. 3,858,630 issued to Cherry et al. on Jan. 7, 1975, discloses a router guide which uses opposing, variable length arms connected to a central suction/anchor to act as a pantograph to cut out a scaled reproduction of a template traced by one arm.
U.S. Pat. No. 4,324,514 issued to Craven on Apr. 13, 1982 discloses a suction anchored router guide for making straight or arcuate cuts in a piece of sheet metal.
U.S. Pat. No. 4,798,506 issued to Kulp, Jr. on Jan. 17, 1989, shows a router guide with a two-piece, telescopically adjustable arm which, when its length is fixed, defines the radius of travel for a router mounted on the router guide.
U.S. Pat. No. 5,038,841 issued to Larmon Aug. 31, 1991, discloses a router guide with a two-piece arm for guiding a router along an arcuate path of variable radius.
The shortcoming in the prior art devices is the complexity and number of parts inherent in their designs. The device of the present application eliminates the need for complex moving parts and telescoping arms while simultaneously reducing the cost and complexity of the guide. By making the guide base with a one piece construction, the stability and durability of the device can be increased while decreasing the complexity and costs.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.